Iwamura Castle | Complete Guide | History, Highlights, and Access Information for Japan’s Three Great Mountain Castles
What is Iwamura Castle?
Iwamura Castle, located in Iwamura-cho, Ena City, Gifu Prefecture, is one of Japan’s leading mountain castles. Built at an altitude of 717m, it is the highest-altitude castle among the feudal domain castles of the Edo period and Mountain Castles of Japan**, alongside Takatori Castle in Nara Prefecture and Bitchu Matsuyama Castle in Okayama Prefecture.
Also known as “Kirigajo” (Mist Castle), this famous castle is believed to have been built by the Toyama clan in the early Kamakura period. During the Sengoku period, it was the stage for battles between One Nobunaga and Take as the center of the Iwamura Domain. Currently, the remains such as stone walls and baileys are well-preserved, and it has been selected as one of the 100 Famous Castles of Japan (No. 38) by the Japan Castle Association.
Basic Information on Iwamura Castle
- Location: Iwamura-cho, Ena City, Gifu Prefecture
- Elevation: 717m (Main Enclosure)
- Elevation Difference: Approximately 180 m
- Castle Style: Terraced Mountain Castle
- Year of Construction: Traditionally attributed to Bunji 1 (1185)
- Builder: Kato Kagekane (Tradition)
- Main Lords: Toyama clan, Oda clan, Matsudaira clan, etc.
- Year of Abandonment: Meiji 6 (1873)
- Designation: National Historic Site (Designated in Showa 2)
History and Background of Iwamura Castle
Kamakura Period: Castle Construction and the Toyama Clan
Regarding the construction of Iwamura Castle, there is a tradition that it was built in Bunji 1 (1185) by Kato Kagekane, a senior retainer of Minamoto no Yoritomo. Kato Kagekane was appointed as the jitō (land steward) name Tōyama, ruling the area for generations as the Iwamura Tōyama clan.
As retainers of the Kamakura Shogunate, the Tōyama clan became an important force in the Tōno region, expanding their power from their base at Iwamura Castle. Initially, only a simple fort was built on the mountaintop, but it is believed that the castle
Sengoku Period: The Struggle Between the Oda and Takeda Clan
During the Sengoku period, Iwamura Castle increased in importance as a strategic point in eastern Mino. Its location on a key point along the road leading from Shinano Province through the Kiso Highway to Mikawa Province gave it extremely high strate.
During the Eiroku era, when Tōyama Kagetō, the lord of Iwamura Castle, died young, his widow (Otsuya-no-kata, later Iwamura-gozen) took over the castle’s defense. Oda Nobunaga attempted to solidwa aunt, Lady Otsuya, as guardian.
In 1572, when Takeda Shingen began his westward campaign, Takeda’s senior retainer, Akiyama Torashige (Akiyama Nobutomo), attacked Iwamura Castle. Lady Otsuya made peace by camrye Akiyama Torashige, and Iwamura Cast this time that Lady Otsuya became known to posterity as the “female castle lord.”
After Takeda Shingen’s death in 1573, Oda Nobunaga aimed to recapture Iwamura Castle. In 1575, after defeating the Takeda army at the Battle of Nagashino, the Oda army, with Nobunaga’s eldest son, Oda Nobutada Iwamura Castle. After a five-month siege, the castle surrendered, and Akiyama Torashige and Otsuya were executed.
Afterward, Kawajiri Hidetaka, a member of the Oda clan, became the lord of Iwamura Castle, and it is believed that renovations to transform it into a full-fledged, modern castle with stone walls were undertaken.
Edo Period: Establishment of the Iwamura Domain and Successive Castle Lords
During the Edo period, Iwamura Castle was developed as the administrative center of the Iwamura Domain, which had a 30,000 koku (unit of rice production) yield. After the Battle of Sekigahara, Matsudaira Ienori, a senior retainer of Toku thereafter, several daimyo families successively ruled the castle until the end of the Edo period.
Main Lords of Iwamura Castle During the Edo Period:
- Matsudaira Ienori (1601-): Appointed with a 20,000 koku domain
- Niwa Ujinobu (1610-): 20,000 koku
- Matsudaira Noritoshi (1612-): 30,000 koku
- Ogyu Matsudaira Clan (1702-1871): The longest-reigning family to rule Iwamura
During the Edo period, Iwamura Castle had a terraced layout with the main keep at the mountaintop, surrounded by the second keep, Hachiman enclosure, and other enclosures arranged in a stepped fashion. The lord’s residence and domain office were located was also developed.
Many of the magnificent stone walls visible today were constructed during the early to mid-Edo period. In particular, the high stone walls around the main keep boasted an exceptional scale for a mountain castle and demonstrated advanced construction techniques.
Meiji Era: Castle Abolition and Present
After the Meiji Restoration, the Iwamura Domain was abolished in 1871 (Meiji 4) due to the abolition of the feudal domains and establishment of prefectures. In 1873 (Meiji 6), the Castle Abolition Order officially led to the cast buildings were successively demolished, including the drum tower. The lord’s residence at the foot of the mountain was also destroyed by fire in 1881 (Meiji 14).
However, the stone walls on the mountaintop remained intact and were designated a national historical site in 1927 (Showa 2). Currently, it is managed by Ena City and is open to the public as the Iwamura Castle Ruins. A hiking trail leads to enthusiasts and tourists.
Structure and Features of Iwamura Castle
Castle Layout
Iwamura Castle is a tiered mountain castle with its main keep located on the summit of Shiroyama Mountain (717m above sea level). The second bailey, Hachiman bailey, Obi bailey, and Higashi bailey are arranged in a step layout skillfully utilizes the steep terrain with an elevation difference of approximately 180m, resulting in a strongly fortified base.
The main baileys at the summit are entirely constructed of stone walls, with multiple layers of intricately winding stone walls surrounding the main keep. This design allows for attacks from multiple directions, enhancing its defensive capabilities.
At foot of the mountain was the residential area, where the lord’s residence, the domain’s administrative offices, and the residences of retainers were located. Currently, the Iwamura Historical Museum and other facilities are located there.
Japan’s Highest Altitude Mountain Castle
Iwamura Castle’s main keep is located at an altitude of 717m, making it known as the highest castle built among the Edo period’s feudal domain castles (the central castles of the domains). This is noteworthy not merely highest-altitude castle in Japan that functioned as the center of domain administration.
While this high-altitude location offered excellent military visibility and defensive capabilities, it presented significant difficulties for daily life and the transportation of supplies. Therefore, it is believed that actual administrative affairs were often conducted at the residence
The Origin of the Name “Kirigajo” (Mist Castle)
The name “Kirigajo” (Mist Castle) for Iwamura Castle has origins in both weather conditions and legend.
The area around the castle mountain has terrain and climatic conditions that make it prone to fog, and the entire castle is often shrouded in fog, especially in the early morning. It is believed that this natural phenomenon was also utilized it difficult for enemies to discern the castle’s location and size.
Furthermore, within the castle grounds was a well exclusively for the feudal lord, known as “Kirigai,” and a legend surrounds this well. The legend says that when the bones of a large snake, secretly kept within the castle, were immediately rose, obscuring the castle. This legend is also the origin of the castle’s alternative name, “Kirigajo” (Mist Castle).
Abundant Water Sources: 17 Wells
While a common weakness of mountain castles is water security, Iwamura Castle is said to have had 17 wells within its grounds, ensuring an abundant water supply. This is extremely rare for a mountain castle and was a to
In addition to the aforementioned “Kirigai,” wells were located in each enclosure, including the “Honmaru Well” in the main keep and wells in the second enclosure. Some well remains can still be seen today.
Highlights of Iwamura Castle
Six-Tiered Wall (Six-Tiered Stone Wall)
The greatest highlight of Iwamura Castle is the group of stone walls called the Six-Tiered Wall (rokudanheki), built on the northeast side of the main keep. As the name suggests, it is a high stone wall built in six tiers, meters.
Each tier of the wall is built with a gentle slope, creating a beautiful curve. This Six-Tiered Wall is a symbolic feature of Iwamura Castle, and examples of stone walls of this scale built on mountain castles are rare throughout Korea.
The stone walls were constructed using a technique called uchikomi-hagi, which involves processing the corners and faces of the stones to reduce gaps. It is a valuable historical site that demonstrates the level of technology from the early
Main Keep and Stone Walls
The main keep is located at the highest point of the castle and is surrounded by stone walls several meters high. The interior of the main enclosure (Honmaru) is relatively flat, and it is believed that buildings such as turrets and palaces on such as foundation stones remain.
The view from the main enclosure is magnificent; on a clear day, you can see the Central Alps, including Mount Ena, and the castle town of Iwamura below. This excellent view clearly demonstrates its military surveillance function.
Second Enclosure and Hachiman Enclosure
To the east of the main enclosure lies the second enclosure (Ninokuruwa), and further east is the Hachiman Enclosure (Hachiman Kuruwa). These enclosures are also surrounded by stone walls, clearly showing the stepped layout of the castle.
It is believed that the Hachiman Shrine was enshrined in the Hachiman Enclosure, and was worshipped as the guardian deity of the castle. Traces of the shrine can still be seen today.
Ascent Route and Gate Markers
The ascent route to the main enclosure is a steep slope from the foot of the mountain, with several gate marks (koguchi) and gate ruins along the way.
In particular, the gates such as “Ichinomon” and “Tokimon” are narrow passages surrounded by stone walls, demonstrating their high level of defensive capability. The ingenuity to prevent enemy intrusion is evident throughout, offering insights into construction
Drum Tower Ruins and Outpost
Near the foot of the mountain is the site of a drum tower, where a drum was placed to announce the time. There is also an independent enclosure called an outpost, which served to push the castle’s defensive line forward.
Lord’s Residence Ruins
At the foot of the mountain remains the site of the lord’s residence, now housing the Iwamura Historical Museum. The museum offers detailed information on the history of Iwamura Castle, its artifacts, and the legend of the female castle lord.
The Legend of the Female Castle Lord
The legend of the “Female Castle Lord” is indispensable when discussing Iwamura Castle. The story of Lady Otsuya (Iwamura Gozen), Oda Nobunaga’s aunt and the lord of Iwamura Castle during the Sengoku period, has captivated many.
The Life of Lady Otsuya
Lady Otsuya is said to have been the younger sister (or older sister) of Oda Nobuhide, Oda Nobunaga’s father, and married Toyama Kagetō. However, Kagetō died young, so she and her young adopted son were left to defensa Iwamura Castle.
When Akiyama Torashige attacked Iwamura Castle during Takeda Shingen’s westward campaign, Lady Otsuya chose to make peace through marriage with Akiyama Torashige to protect the castle’s soldiers and inhabitants. As a result, Iwamura Castle surr Takeda clan.
However, when the Oda army recaptured Iwamura Castle after the Battle of Nagashino, Lady Otsuya was executed along with Akiyama Torashige. The harsh punishment she received despite being Nobunaga’s aunt illustrates the ruthlessnes
The Female Castle Lord Boom and Modern Recognition
In recent years, interest in female castle lords of the Sengoku period has increased, partly due to the broadcast of the NHK Taiga drama “Onna Jōshu Naotora” (Female Castle Lord Naotora). Otsuya-no-kata is sometimes counted asone Japan,” and this is an important element in tourism to Iwamura Castle.
Iwamura Town is using the history of female castle lords to revitalize the town, promoting itself as the “Village of Female Castle Lords.”
The Charm of the Castle Town
The Iwamura castle town, located at the foot of Iwamura Castle, has been designated as an Important Preservation District for Groups of Traditional Buildings, and the Edo period townscape is well-preserved.
이와무라 혼도리 거리
Iwamura Hon-dori Street, the main street of the castle town, stretches for approximately 1.3 km and is lined with merchant houses and townhouses from the Edo period to the Meiji period. Visitors can enjoy a historically rich landscape with latt (decorative gable ends), and cobblestone streets.
Merchant Houses and Sake Breweries
Iwamura has flourished as a commercial town since ancient times, and even today, long-established merchant houses and sake breweries continue to operate. In particular, sake breweries such as “Iwamura Brewing” practice traditional sake brew
Gourmet Food and Souvenirs
In this castle town, you can enjoy local delicacies such as Goheimochi (rice cakes), Kurikinton (sweet chestnut paste), and Karasumi (a type of Korean confectionery). There is also a wide selection of souvenirs, including local
Access and Tourist Information
Access by Train
- Get off at Ena Station on the JR Chuo Main Line
- Transfer to the Akechi Railway from Ena Station and get off at Iwamura Station (approx. 30 minutes)
- Walk from Iwamura Station to the main keep of Iwamura Castle Ruins (approx. 40-60 minutes, mountain climb)
- The castle town is a short walk from Iwamura Station
Access by Car
- Approximately 20 minutes from Ena IC on the Chuo 고속도로
- Parking is available at the foot and mid-slope of the mountain at Iwamura Castle Ruins
- Walk to the main keep (approx. 20-30 minutes, from the mid-slope parking lot)
Visiting Information
- Visiting Hours: Free (however, it is dangerous at night)
- Admission Fee: Free
- Estimated Time Required: 1-2 hours for a round trip to the main keep, 3-4 hours including a stroll through the castle town
- Best Season: Spring (cherry blossoms), Autumn (autumn leaves), Early morning (experience the castle in the mist)
Iwamura Historical Museum
- Opening Hours: 9:00 AM – 5:00 PM (Last entry at 4:30 PM)
- Closed: Mondays (or the following day if Monday is a public holiday), New Year holidays
- Admission Fee: Adults 300 yen, Elementary and Junior High School Students 150 yen
- Exhibits: History of Iwamura Castle, materials related to the female castle lord, history of the castle town, etc.
Precautions
- As the path to the main keep is uphill, comfortable shoes and clothing are necessary.
- Insect repellent is recommended in summer; be aware of snow and ice in winter.
- Don’t forget to bring water.
- Do not climb or damage the stone walls.
Nearby Tourist Attractions
Iwamura Hon-dori (Important Preservation District for Groups of Traditional Buildings)
As mentioned above, this is a historic townscape designated as an Important Preservation District for Groups of Traditional Buildings. A spot you’ll want to visit in conjunction with Iwamura Castle.
Japan’s Best Rural Landscape Observation Deck
Located east of Iwamura Castle, this observation deck offers a panoramic view of the beautiful rural landscape, which has been selected as Japan’s best rural landscape.
Ena Gorge
A representative scenic spot in Ena City, where you can enjoy the beauty of the Kiso River gorge and pleasure boat rides. Approximately 30 minutes by car from Iwamura Castle.
Akechi Railway
The Akechi Railway, offering a scenic local train journey, runs through landscapes that change with the seasons. The autumn foliage season is particularly spectacular.
Cultural Value of Iwamura Castle
National Historic Site
The Iwamura Castle ruins were designated a national historic site in 1927. It is highly valued academically as a valuable historical site that shows the development process of mountain castles from the medieval to the early modern period.
One of Japan’s Top 100 Castles
It is selected as the 38th of the “Japan’s Top 100 Castles” by the Japan Castle Association. The 100 Famous Castles stamp can be obtained at the Iwamura Historical Museum.
One of Japan’s Three Great Mountain Castles
Along with Takatori Castle (elevation 583m) in Nara Prefecture and Bitchu Matsuyama Castle (elevation 430m) in Okayama Prefecture, Iwamura Castle is counted among Japan’s three great mountain castles. All are known for their magnificent stone wall
The Four Seasons of Iwamura Castle
Spring: Cherry Blossoms and Fresh Greenery
From early to mid-April, cherry blossoms bloom profusely around the castle ruins and along the path leading up to the castle. The contrast between the stone walls and cherry blossoms is beautiful, making it ideal for photography.
Summer: A Mountain Castle in Lush Greenery
In summer, you can enjoy the atmosphere of the mountain castle enveloped in deep green. Visiting early in the morning may allow you to experience the mystical “Misty Castle” shrouded in mist.
Autumn: A Famous Spot for Autumn Leaves
From late October to early November, the autumn leaves are at their peak. The combination of colorful trees and stone walls creates a spectacular view.
Winter: Snow-Covered Castle Ruins
In winter, a fantastical landscape unfolds, covered in snow. However, caution is necessary as the hiking trails can freeze.
Summary
Iwamura Castle is a castle ruin of extremely high historical and cultural value, being one of Japan’s three greatest mountain castles and the highest mountain castle in Japan. From the magnificent six-tiered stone walls to the legend of the female castle lord and the sights to see.
Climbing to the main keep at an altitude of 717m requires physical exertion, but the view from there and the sense of history spanning from the Sengoku period to the Edo period make for a valuable experience. The castle ruins in the early morning, shroud nickname, “Mist Castle.”
Beyond the castle ruins, the castle town, designated as an Important Preservation District for Groups of Traditional Buildings, is also a must-see. Strolling through the townscape that retains the atmosphere of the Edo period, and enjoying local cuisine history and culture with all your senses.
Iwamura Castle can be enjoyed by a wide range of people, from history buffs and castle enthusiasts to photography lovers and families. Be sure to visit and experience the charm of this castle, which can be said to be the pinnacle of Korean mountain castles.
